Time delay control device



Oct. 19, 1965 S. J. MIKINA ETAL TIME DELAY CONTROL DEVICE Filed Feb. 21, 1962 mg TH I07 I 6| 97 5;: 55 I 59 i I I 53 a3 BII 9 I 2 ;3 79

S Sheets-Sheet l ATTORNEY Oct. 19, 1965 s. J. MlKlNA ETAL 3,213,237

TIME DELAY CONTROL DEVICE Filed Feb. 21, 1962 s Sheets-Sheet 2 TIME DELAY IN SECONDS O 2 3 5 6 7 8 9 IO ll l2 NUMBER OF TURNS UNSCREWED FROM ALL IN POSITION 1965 s. J. MlKlNA ETAL 3,213,237

TIME DELAY CONTROL DEVICE Filed Feb. 21, 1962 3 Sheets-Sheet 3 United States Patent 3,213,237 TIME DELAY CONTROL DEVICE Stanley Joseph Mikina, Penn Hills, and Merrideth D. Wilsou, Monroeville, Pa., assignors to Westinghouse Electric Corporation, East Pittsburgh, Pa., a corporation of Pennsylvania Filed Feb. 21, 1962, Ser. No. 174,818 Claims. (Cl. 20097) This invention relates generally to control devices, and more particularly to time delay mechanisms and to elec trical control structures of the type comprising a time delay mechanism.

In the control art, the flow of fluid or air through an orifice from or into a varying volume is often utilized as the means for providing a time interval between an actuation and a response to the actuation. In the prior art, time delays have often been effected by changing the volume of a deformable chamber against the force of a biasing spring, and then letting the charged spring restore the chamber to its initial volume by forcing air through a tapered-needle type valve that connects the chamber to another atmosphere. The time delay has been varied by a screw-type adjustment of the needle relative to a valve seat to vary the dimension of the orifice through which the fluid flows.

There are basic disadvantages to this prior art variableorifice type of timing apparatus. A plotted curve of the time delay versus the needle valve travel is non-linear. The time delay is substantially proportional to the inverse first power of the needle displacement from its seat. Hence, for the longer delays obtained with the needle valve nearly closed, a small amount of needle displacement will result in a comparatively large change in the time delay, thus making the needle valve adjustment more critical. At the opposite end of the scale, when the needle is far off its seat for short time delays, a comparatively large amount of needle travel is required to effect a change in the time delay. Thus, at each time delay setting, a difierent rate of change of time delay per unit of needle valve adjusting screw rotation exists so that it is relatively difficult to determine how far to move the adjusting screw to effect a given change in the time delay to fit a particular operational requirement. Moreover, the impedance to fiuid flow occurs at the relatively short needle valve in this type of apparatus. Thus, for a given delay time, the orifice opening is relatively small and hence relatively more vulnerable to a change of calibration as a result of dirt particles that may become lodged in the orifice. Furthermore, the annular shaped valve opening is extremely small when the device is adjusted for long time delays so that, in order to obtain calibration repeatability under these conditions, very close manufacturing tolerances must be maintained on the needle valve surfaces, and on the mating valve seat.

Accordingly, an object of this invention is to provide an improved time delay mechanism that has a linear adjustment feature and that is less vulnerable, due to a relatively large orifice opening, to changes in calibration due to dirt particles that may become lodged in the orifice.

Another object of this invention is to provide an improved time delay mechanism having a novel type of adjustable fluid flow path.

A more general object of this invention is to provide an improved time delay mechanism.

Another object of this invention is to provide an improved electrical control structure that operates with a time delay.

A further object of this invention is to provide a time delay mechanism having an improved valve mechanism.

A still further object of this invention is to provide an improved electrical control structure comprising a time 1 3,213,231 Patented Oct. 19, 1965 delay mechanism having an improved valve mechanism therein.

Other objects of this invention will be explained fully hereinafter or will be apparent to those skilled in the art.

The invention, both as to structure and operation, together with additional objects and advantages thereof, will be best understood from the following detailed description thereof when read in conjunction with the accompanying drawings.

In said drawings:

FIGURE 1 is a sectional view taken generally along the line II of FIG. 2 illustrating a control device embodying principles of this invention;

FIG. 2 is a sectional view taken generally along the line IIII of FIG. 1;

FIG. 3 is an enlarged sectional view illustrating part of the time delay mechanism seen in FIGS. 1 and 2;

FIG. 4 is a table illustrating certain test results;

FIG. 5 is a sectional view taken generally along the line V-V of FIG. 6 illustrating a different control device embodying principles of this invention; and

FIG. 6 is a sectional view taken generally along the line VIVI of FIG. 5.

Referring to the drawings, there is shown, in FIGS. 1 and 2, a control device 5 comprising a control structure 7 and a time delay mechanism or apparatus 9. The control structure 7 may be a contactor or relay or other similar type of electromagnetic control structure. As shown in the drawings, the control structure 7 is a relay that, except for the contact carrier structure that will be hereinafter specifically described, is of a type specifically described in a copending patent application of Gustav Jakel, Serial No. 848,779, filed October 26, 1959 now Patent Number 3,088,058. For this reason, only a brief description of the relay 7 is given herein.

The relay 7 comprises a housing comprising a base 13 and cooperating cover 15 both of which are of insulating material. The base 13 and cover 15 are held firmly together as a unit by means of bolts (not shown) that are disposed at diagonal corners of the housing. The relay 7 is supported on a base plate 17 by means of screws that pass through the insulating housing 13, 15. An E- shaped main magnet or core member 19 is supported in the housing base 13. As is seen in FIG. 1, the legs of the E-shaped core member 19 extend upwardly. A magnetizing winding, or coil 21 is disposed on a suitable spool 23 of insulating material. The spool 23 and coil 21 are positioned over the middle leg of the E-shaped core member 19. Two terminals 25 (only one of which is shown in FIG. 2), are provided at diagonal corners of the relay 7 to enable connection of the coil 21 in an electric circuit.

An E-shaped armature member 27 is provided to cooperate with the core member 19. The armature member 27 is connected to a molded insulating outer contact carrier 29 by means of a bolt 30 which bolt pivotally mounts the armature 27 on the contact carrier 29 so that the armature, within certain limits, has freedom of rotation in the plane of the paper, as seen in FIG. 1.

The relay 7 comprises four pole units, each of which pole units comprises two oppositely disposed stationary contact structures 31 (FIG. 1) that are supported on the upper housing part 15 by means of terminal screws 33. A stationary contact 35 is provided at the free end of each of the stationary contact structures 31. A movable bridging contact member 37 having a contact 39 at each of two opposite ends thereof, is provided to bridge the contacts 35 in each pole unit. As seen in FIG. 1, the contacts are shaped and disposed so that the position of the contacts when the solenoid coil 21 is deenergized will be normally closed; the bridging contact member 37 being adapted to move down to an open position in a manner to be hereinafter specifically described. The contact structures can, however, be constructed and shaped to be normally open as seen in FIG. 5. As seen in FIGS. 1 and 2, all of the contact structures of the four pole units are constructed to be normally closed. This is a matter of choice and, depending upon particular control requirements, the relay can be adapted to have any combination of normally open and normally closed contacts in a manner well known in the art.

The outer contact carrier 29, which is attached to and movable with the armature 27, controls and carries only the two bridging contact members 37 of the outer (FIG. 2) two pole units. The bridging contact members 37 for the two inside (FIG. 2) pole units are carried by a separate inner insulating contact carrier 41 which inner contact carrier is operable to control movement of the two inner bridging contact members 31 after a time delay in a manner to be hereinafter specifically described. Each of the bridging contact members 37 is disposed in an opening 42 (FIG. 2) in the associated contact carrier and is held in position by means of a spring 43 that also provides contact pressure when the contacts are in the closed position.

The time delay mechanism or apparatus 9 comprises an insulating base member 47 supported on a pair of brackets 49 that are secured to the relay 7 by means of bolts 51. The wall of the time delay apparatus 9 comprises a cylinder 53 that is supported on the base member 47. A block 55 is supported on the cylinder 53 by means of screws 57 that pass through a ring-shaped plate 59 and a flange portion of the cylinder 53 (FIGS. 1 and 2) which screws engage in tapped openings in the block 55. An O-ring sealing member 61 is disposed near the top of the block 55 and supported thereon by means of two screws 63. An adjusting structure 69 (to be hereinafter specifically described) is supported on the block 55.

The time delay mechanism 9 also comprises a pushrod structure 71 and a bellows member 73 having a valve seat portion 74. The push-rod structure 71 comprises a lower rod portion 75, a shoulder portion 77, a valve 79 and an upper rod portion 81. When the armature 27 is in the open position seen in FIGS. 1 and 2, the push-rod structure 71 rests on, but is not attached to, the top of the armature 27. A spring 83 disposed within the bellows valve chamber, engages the top of the valve seat 79 to bias the push-rod structure 71 into engagement with the armature 27. A spring 85 that is provided outside of the bellows chamber and that is weak er than the spring 83, is provided to return the bellows valve 73 to the compressed condition seen in FIGS. 1 and 2 after a time delay operation in a manner to be hereinafter specifically described. Two springs 87 (FIG. 1) bias the inner contact carrier 41 downward which movement is restrained by engagement of the contact carrier 41 with two bell-crank type latches 89 (FIG. 2). The latches 89 are biased to the latching position shown in FIG. 2 by means of torsion springs (not shown). The bell-crank type latches 89 are pivotally supported on the brackets 49 by means of pivot pins 91.

The bellows valve 73 is secured to the block 55 by means of a ring-shaped plate 93 (FIG. 3) that is secured to the block 55 by means of screws (not shown).

There are three chambers within the time delay apparatus 9. These chambers comprise a lower chamber 95, an upper chamber 97 and a bellows chamber 99. A filtered passage (not shown) is provided for permitting air to filter into the upper chamber 97 from the outer atmosphere. As is best seen in FIG. 3, the upper chamber 97 is connected to the lower chamber 95 by means of two orifices or passages 101 in the block 55. The upper chamber 97 is connected to the bellows chamber 99 by means of a flow passage 105 (FIG. 3). The block 55 is tapped to form internal threads 106. The adjusting structure 69 comprises a handle portion 107 and a member 109 having external threads 110 formed there- 4 on. The member 109 is screwed into the tapped opening of the block 55. The threads 110 of the member 109 are so shaped that they do not completely fill the tapped portion of the block 105 so that the threads 109 and 110 cooperate to form a helical flow passage that is generally triangular in cross section and that connects the bellows chamber 99 with the upper chamber 97. The adjusting structure 69 can be screwed into or out of the block to adjust the length of the helical flow passage 105. As is seen in FIG. 3, the adjusting structure 69 could be rotated in one direction to raise the member 109 to thereby provide a shorter flow passage 105, and thereafter, the adjusting structure 69 could be rotated in the opposite direction to lower the member 109 to lengthen the flow passage 105.

The operation of the control device 5 is as follows:

As seen in FIGS. 1 and 2, the control device 5 is shown with the coil 21 deenergized and the contacts 35, 39 of all of the four pole units in the normally closed position. In operation, when the coil 21 is energized, the armature 27 is attracted to move down and engage the core member 19. This movement of the armature 27 carries the outer contact carrier 29 and the two bridging contact members 37 for the outer (FIG. 2) two pole units downward to open the contacts 35, 39 for the outer two pole units. The inner contact carrier 41 remains in the upper position seen in FIGS. 1 and 2 because it is latched there by the bell-crank type latches 89. When the armature 27 moves downward, it moves away from the push-rod structure 71 whereupon the spring 83, which is stronger than the spring 85, biases the valve seat 79 to force the push-rod structure 71 downward expanding the bellows 73. This downward movement of the pushrod structure 71 is delayed because the rate of expansion of the bellows 73 is determined by the rate at which the air or fluid is sucked into the chamber 99 through the flow passage 105 (FIG. 3). As is best seen in FIG. 3, as the bellows 73 expands, fluid, or air in this instance, is sucked from the chamber through the orifices 101, into the chamber 97, through the helical flow passage and into the bellows chamber 99. Thus, the push-rod structure 71 moves downward under the force of the spring 83, which rate of movement is controlled by the rate of flow of fluid through the helical passage 105.

The push-rod structure 71 moves to a position wherein the shoulder 77 thereon engages the free ends 111 (FIG. 2) of the bell-crank latches 89 to rotate the bell-crank latches 89 to unlatch the inner contact carrier 41, whereupon the springs 87 (FIG. 1) expand to move the inner contact carrier 41 and the inner two bridging contact mem bers 37 that are carried by the inner contact member 41 down to the open position. Thus, the actuation of the two inner (FIG. 2) pole units is delayed by the time delay mechanism 9.

After operation of the inner contact carrier 41, and when the coil 21 is deenergized, the armature 27 is moved back up to the position seen in FIGS. 1 and 2 by means of two springs 115 (only one of which is shown in FIG. 2). The springs 115 and 85 are stronger than the springs 87 and 83 (FIG. 1) and, as the armature 27 moves up moving the outer contact carrier 29 which is attached to the armature upward, the contact carrier 29 engages a portion of the inner contact carrier 41 to force the inner contact carrier up to the position seen in FIGS. 1 and 2 charging the springs 87 (FIG. 1). As the armature 27 is moved upward, it engages the push-rod structure 71 to move the push-rod structure 71 upward charging thespring 83. When the inner contact carrier 41 reaches thev position seen in FIGS. 1 and 2, it is again latched by means of the bell-crank type latches 89.

As the push-rod structure 71 is moved to the upper position seen in FIGS. 1 and 2, the valve 79 is moved away from the valve seat 74 of the bellows; valve 73, and the spring 85 operates to collapse the vative 73 until the valve seat 74 is again seated against the valve 72.

valve 73 can be Collapsed under the force of the relatively weak spring 85, because, as the push-rod structure 71 moves upward moving the valve 79 upward, the air can freely pass past valve seat 74 from inside the chamber 99 out into the chamber 95.

The results of tests conducted on a control device similar to that seen in FIGS. 1 and 2 are illustrated in the table seen in FIG. 4. In the tested structure, the outside diameter of the screw member 109 was .359 inch and the outside diameter of the mating thread or tapped opening of the member 55 was .375 inch. There were 12 threads in a inch length. As can be seen in the graph, the time delay in seconds, in response to the number of turns unscrewed from the all-in position, is graphed as a substantially straight line. As was explained in the introduction, this linear adjustment characteristic is advantageous in an adjustable time delay mechanism. Although the control device tested had a maximum time delay of 43.2 seconds, it is to be understood that the time delay could be lengthened if desired by merely lengthening the orifice or flow passage 105. Control devices have been constructed in accordance with the principles of this invention with an upper limit of time delay of 60 seconds, which control devices still had the desirable linear adjustment characteristic.

It is desirable to have an interference-type fit between the members 55 and 109 to seal the thread flanks effectively to confine the air flow to the defined flow passage 105. There also should be a IOW-COBffiClCn't of friction between the members 55 and 109 in order to permit easy rotation of the adjusting structure 69. The members 55 and 69 can be either machined or molded to the desired shapes. In one control device that has been constructed in accordance with the principles of this invention and tested successfully, the member 55 comprises a block of polycarbonate resin material having the tapped opening machined therein, and the adjusting member 109 comprises a member molded from polytrichlorfluoroethylene, which material is a polyfluorocarbon known under the proprietary name of Teflon.

The time delay of the control device described and shown in FIGS. 1 and 2 is effected after the energization of the coil 21 and movement of the armature 27 into engagement with the magnetic member 19. A control device 5 is shown in FIGS. 5 and 6 which is similar to the control device of FIGS. 1 and 2 except that the control device of FIGS. 5 and 6 is constructed to operate with a time delay after deenergization of the coil 21 and after movement of the armature 27 to the open position seen in FIG. 5. Parts of the control device 5' seen in FIGS.

5 and 6 that are like parts of the control device 5 seen in FIGS. 1 and 2, have reference characters applied thereto that are the same as the reference characters of the like parts of the control device 5.

Although the contacts 35, 39 seen in FIGS. 5 and 6 are normally opened rather than normally closed, it is to be understood that the control device 5 can be constructed to operate with the contacts 35, 39 normally opened, normally closed or, in the different combinations of normally opened and normally closed that are readily apparent to a person skilled in the art.

The push-rod type structure 71 of the control device 5 comprises a lower part 117 and an upper portion 119 which parts are connected together by means of a lost motion connection. A retaining disc 121 is attached to the upper part 119 and a pin 123 in the lower part 117 engages the disc 121 when the part 117 is moved downward to thereby pull the part 119 downward, and a slot 125 is provided in the upper part 119 to permit upward movement of the lower part 117 relative to the upper part 119. The lower part 117 has a plate 129 attached to its lower end, which plate 129 engages under a portion of the inner contact carrier 29 so that the push-rod structure 71 will be pulled downward with the armature 27 and contact carrier 29. It is also to be noted that springs 133 (FIG. 5) are provided to bias the inner contact carrier 41 upward to distinguish from the downward bias of the contact carrier 41 in FIGS. 1 and 2. The valve 79 of the push-rod structure 71 is disposed outside of the bellows 73 and a spring 135, which biases the valve 79 upward, is stronger than a spring 137 that is disposed inside of the bellows 73 to bias the bellows 73 toward the expanded position. Another difference between the control device 5' and the control device 5 is that the contact carrier 41 is latched in the lower, rather than upper, position by means of two bell crank type latches 141 (FIG. 6). The operation of the control device 5' is as follows:

As seen in FIGS. 5 and 6, the control device 5' is shown with the bridging contact members 37 in the normally opened position and the armature 27 in the upper position with the coil 21 deenergized. When the coil 21 is energized, the armature 27 is attracted to move down to engage the core member 19. During this movement, the armature 27 carries the outer contact carrier 29 with it to move the bridging contact members 37 of the two inner (FIG. 6) pole units to the closed position. As the outer contact carrier 29 moves downward, it pulls the plate 129 down with it moving the push-rod structure 71 down compressing the spring 135 beneath the valve 79 and allowing the spring 137 to expand the bellows 73 until the bellows valve seat 74 seats against the valve 79. As the push-rod structure 71 is pulled down, a disc 145 that is attached to the part 117 engages the inner contact carrier 41 to move the inner contact carrier 41 and the two inner (FIG. 6) bridging contact members 37 down to the closed position. During this movement, the springs 133 (FIG. 5) are compressed between the inner contact carrier 41 and the top of the housing part 15. When the inner contact carrier 41 reaches the closed position, the bell-crank type latches 141 (FIG. 6) are rotated by torsion springs (not shown) to positions wherein the ends 149 thereof engage the upper portion of the contact carrier 41 to latch the contact carrier 41 in the closed position. Thus, it can be understood that when the coil 21 is energized the armature 27 is moved down to simultaneously move both of the contact carriers 29 and 41, and all of bridging contact members 37, down to the closed position.

Thereafter, when the coil 21 is deenergized, the armature 27 is moved, under the bias of the springs 115, back up to the position in which it is seen in FIG. 5. During this movement, the armature 27 carries the outer contact carrier 29 and the two bridging contact members 37 for the outer (FIG. 6) two pole units up to the open position.

As the armature 27 moves up to the open position, it engages the member 129 to move the part 117 of the pushrod structure 71 upward. The pin 121 of the part 117 moves in the slot of the part 119, so that part 119, which is restrained by the bellows valve 73, does not move up with the part 117. The part 119, however, starts to move up under the bias of the spring which spring biases the valve 79 upward to force the bellows 73 to collapse charging the spring 137. The rate of collapse of the bellows '73 is determined by the rate of flow of air out of the bellows chamber 99, through the adjustable helical flow passage 105 (FIG. 3), into the upper chamber 97, through the orifices 101 and into the lower chamber 95. This rate of air flow is determined by the rate of air flow through the helical flow passage 105 (FIG. 3) which flow passage is adjustable in the same manner as was hereinbefore described.

The part 119, therefore, moves up at a rate determined by the adjusted setting of the adjusting structure 69, and, after a predetermined time delay, the disc 121 on the part 119 engages the free ends of the two bell-crank latches 141 rotating these latches to move the latch portions 149 thereof inwardly to unlatch the inner latch carrier 41, whereupon the charged springs 133 (FIG. 5) expand driving the inner contact carrier 41 and the briding contact members 37 for the two inner pole units to the open position. The parts of the control device are thereafter in position for another cycle of operation.

The control device 5 of FIGS. 1 and 2 is called an on delay control device because the time delay is effected after the coil 21 is energized. The control device 5 of FIGS. 5 and 6 is called an off delay control device because the time delay is effected after deenergization of the coil 21. Thus, it can be understood that the terms on delay and oil? delay are not descriptive of the contact positions, which positions, as was hereinbefore mentioned, can be varied depending upon the particular control requirements.

From the foregoing, it will be understood that there is provided by this invention an improved control device comprising an improved time delay mechanism with a novel fluid flow passage that is adjustable to vary the amount of time delay. The novel time delay mechanism can be used with both an on delay and an ofl? delay control device. The off delay control device herein described comprises a novel combination and arrangement of parts representing an improvement over the prior art wherein a more complex motion reversing mechanism was used to convert an on delay bellows valve type mechanism to an off delay bellows valve type mechanism.

Since numerous changes may be made in the above described construction, and different embodiments of the invention may be made without departing from the spirit and scope thereof, it is intended that all matter contained in the foregoing description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

We claim as our invention:

1. A time delay mechanism comprising, in combination, a bellows valve having an opening therein, a first resilient means disposed inside of said bellows valve, an adjustable flow passage connecting the inside of said bellows valve with a separate atmosphere, a movable structure comprising a valve member disposed outside of said bellows valve, a second spring biasing said valve member toward said bellows valve to close said opening, said valve member being movable away from said bellows valve by a force great enough to compress said second spring to thereby open said opening whereupon said first spring expands said bellows valve, and when the application of said force is discontinued said second spring moving said valve member against said bellows valve closing said opening and compressing said bellows valve and said first spring, the rate of compression of said bellows valve being determined by the rate of flow of fluid from said bellows valve through said adjustable flow passage.

2. A time delay mechanism comprising, in combination, a bellows valve having an opening at one end thereof and a valve seat adjacent said opening, a first spring disposed inside of said bellows valve, an adjustable flow passage positioned at the other end of said bellows valve and connecting the inside of said bellows valve with a separate atmosphere, a movable push-rod structure comprising a valve member disposed outside of said bellows valve, a second spring biasing said valve member into engagement with said valve seat, said push-rod structure being movable away from said bellows valve by a force great enough to compress said second spring to thereby open said opening whereupon said first spring expands said bellows valve, and when the application of said force is discontinued said second spring moving said valve against said valve seat closing said opening and compressing said bellows valve and said first spring, the rate of compression of said bellows valve being determined by the rate of flow of said fluid from said bellows valve through said flow passage, and means for adjusting said flow passage to vary the rate of flow of fluid through said flow passage.

3. A control device comprising a control structure and a time delay apparatus, said control structure comprising, a core member, a coil positioned to magnetically energize said core member, an armature movable relative to said core member and supported to cooperate with said core member, a stationary contact structure, a movable contact structure cooperable with said stationary contact structure to open and close an electric circuit, when said coil is electrically energized said core member being magnetically energized to attract said armature whereupon said armature is drawn toward said core member, said time delay apparatus comprising a bellows valve having an opening therein, a first resilient means disposed inside of said bellows valve, a fluid flow passage connecting the inside of said bellows valve with a separate atmosphere, a movable push-rod structure comprising a valve member disposed outside of said bellows valve, a second resilient means biasing said valve member toward said bellows valve, said push-rod structure being connected to said armature to move away from said bellows valve when said armature is attracted to said core member to thereby open said opening whereupon said first resilient means operates to expand said bellows valve, means on said pushrod structure operating to move said movable contact structure from a first operating position to a second operating position when said push-rod structure is moved with said armature movement, means latching said movable contact structure in said second operating position, when said coil is deenergized said armature moving away from said core member to said first position, said push-rod structure comprising two parts having a lost motion connection therebetween to permit movement of a first of said parts with said movement of said armature away from said core member whereupon said second resilient means moves said second portion and said valve against said bellows valve closing said opening and compressing said bellows valve and said first spring, the rate of compression of said bellows valve being determined by the rate of flow of fluid from said bellows valve through said fluid flow passage, means on said second part operating to unlatch said latching means when said second part reaches a predetermined position to thereby release said movable contact structure, and means operating when said movable contact structure is released to move said movable contact structure from said second operating position to said first operating position.

4. A time delay mechanism comprising, in combination, a bellows valve having an opening therein, a first resilient means disposed inside of said bellows valve, an adjustable helical flow passage connecting the inside of said bellows valve with a separate atmosphere, a movable structure comprising a valve member disposed outside of said bellows valve, a second spring biasing said valve member toward said bellows valve to close said opening, said valve member being movable away from said bellows valve by a force great enough to compress said second spring to thereby open said opening whereupon said first spring expands said bellows valve, and when the application of said force is discontinued said second spring moving said valve member against said bellows valve closing said opening and compressing said bellows valve and said first spring, the rate of compression of said bellows valve being determined by the rate of flow of fluid from said bellows valve through said adjustable helical flow passage.

5. A control device comprising a control structure and a time delay apparatus, said control structure comprising a core member, a coil positioned to magnetically energize said core member, an armature movable relative to said core member and supported to cooperate with said core member, a stationary contact structure, a movable contact structure cooperable with said stationary contact structure to open and close an electric circuit, when said coil is electrically energized said core member being magnetically energized to attract said armature whereupon said armature is drawn toward said core member, said time delay apparatus comprising a bellows valve having an opening therein, a first resilient means disposed inside of said bellows valve, an adjustable helical fluid flow passage connecting the inside of said bellows valve with a separate atmosphere, a movable push-rod structure comprising a valve member disposed outside of said bellows valve, a second resilient means biasing said valve member toward said bellows valve, said push-rod structure being connected to said armature to move away from said bellows Valve when said armature is attracted to said core member to thereby open said opening whereupon said first resilient means operates to expand said bellows valve, means on said push-rod structure operating to move said movable contact structure from a first operating position to a second operating position when said push-rod structure is moved with said armature movement, means latching said movable contact structure in said second operating position, when said coil is deenergized said armature moving away from said core member to said first position, said push-rod structure comprising two parts having a lost motion connection therebetween to permit movement of a first of said parts with said movement of said armature away from said core member whereupon said second resilient means moves said second portion and said valve against said bellows valve closing said opening and compressing said bellows valve and said first spring, the rate of compression of said bellows valve being determined by the rate of flow of fluid from said bellows valve through said adjustable helical fluid flow passage, means on said second part operating to unlatch said latching means when said second part reaches a predetermined position to thereby release said movable contact structure, and means operating when said movable contact structure is released to move said movable contact structure from said second operating position to said first operating position.

References Cited by the Examiner UNITED STATES PATENTS 2,521,202 9/50 Cloudsley ZOO-34 2,538,038 1/51 Ponstingl et a1. 20097 2,899,523 8/59 Flatet et al 20034 2,929,898 3/60 Schaefer 20097 2,976,961 3/61 Mead 188100 X 3,019,317 3/62 Gauvreau 20097 3,037,101 5/62 Komatar et a1 ZOO-34 3,081,847 3/63 Smitley 20034 BERNARD A. GILHEANY, Primary Examiner.

ROBERT K. SCHAEFER, Examiner. 

4. A TIME DELAY MECHANISM COMPRISING, IN COMBINATION, A BELLOWS VALVE HAVING AN OPENING THEREIN, A FIRST RESILIENT MEANS DISPOSED INSIDE OF SAID BELLOWS VALVE, AN ADJUSTABLE HELICAL FLOW PASSAGE CONNECTING THE INSIDE O SAID BELLOWS VALVE WITH A SEPARATE ATMOSPHERE, A MOVABLE STRUCTURE COMPRISING A VALVE MEMBER DISPOSED OUTSIDE OF SAID BELLOWS VALVE, A SECOND SPRING BIASING SAID VALVE MEMBER TOWARD SAID BELLOWS VALVE TO CLOSE SAID OPENING, SAID VALVE MEMBER BEING MOVABLE AWAY FROM SAID BELLOWS VALVE BY A FORCE GREAT ENOUGH TO COMPRESS SAID SECOND SPRING TO THEREBY OPEN SAID OPENING WHERE- 